A cupola is a relatively small, dome-like, tall structure on top of a building that is used to provide a lookout or to admit light and air. It is a hollow frame that protrudes up from the roof of a building and often has pointy roofs and windows or vents on the sides. Cupolas are produced in various shapes and sizes but are commonly square or hexagonal and much smaller than the structure to which they’re attached. They can serve various purposes, but they’re primarily used to add aesthetic appeal to the structure they garnish. Cupolas can also be used for ventilation, especially in rural architecture, where they were originally a necessary ventilation system for keeping livestock cool and dry. Cupolas can appear as small buildings in their own right and can also be found on barns, homes, and garages. They can be functional, decorative, or both. Cupolas can be found in various shapes, including square, round, and octagonal.